Service Tip: Sharpening Rotary Blades

Dull cutting edges and/or bent blades compromise your mower’s quality of cut. Here’s a quick review of the proper sharpening process.

1. Before sharpening the blade, make sure it is straight. Lay the blade on a flat surface to check.

TIP: Do not try to straighten a blade that is bent, and never weld a broken or cracked blade. Always use a new Toro blade to assure continued safety certification of the product.

2. When sharpening the blade, grind the top surface only, trying to maintain the angle of the original cutting edge. Do not grind the bottom surface or a chisel shape will result. The lowest portion on the blade that contacts the grass must be the cutting edge or it will not cut the grass cleanly and excessive horsepower will be required.

TIP: To prevent possible personal injury, wear a face shield or safety glasses while grinding or sharpening a blade.

3. After the blade has been sharpened, check the balance. This is best done using a blade balancer tool. A balanced blade will stay in a horizontal position on the balancer. A blade that is not balanced will settle to the heavy side. If the blade is not balanced, grind some metal off the heavy end of the blade. DO NOT grind the bottom of the cutting edge. This will cause poor quality of cut and require more horsepower.

4. When installing blades, be sure to tighten the blade retaining bolt to the correct torque so it will not loosen during operation. Do not use an air or electric wrench to apply the final torque. To prevent loosening or damaged threads, always use a standard torque wrench to apply the final torque. Check blade retaining bolt torque anytime a blade has hit a solid object.

REMEMBER: If a blade is allowed to wear, a slot will form between the sail and flat part of the blade. Eventually a piece of the sail may break off and be thrown from under the housing, possibly resulting in serious injury to the operator or a bystander.

For more information, see your mower service manual, contact your local Toro distributor or see the technical resources on www.toro.com.